Intel® 820E Chipset

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Traces from magnetics to connector must be shared and not stubbed. An RJ-11 connector that fits into the RJ-45 slot is available. Any amount of stubbing will destroy both HomePNA* and Ethernet performance.

2.22.7.ICH2 Decoupling Recommendations

The ICH2 can generate large current swings when switching between logic high and logic low. This condition could cause the component voltage rails to drop below the specified limits. To avoid such a situation, ensure that the appropriate amount of bulk capacitance is added in parallel with the voltage input pins. It is recommended that the developer use the number of decoupling capacitors specified in the following table, to ensure that the component maintains stable supply voltages. The capacitors should be placed as close as possible to the package. Refer to Figure 78 for a layout example. For prototype board designs, it is recommended that the designer include pads for extra power plane decoupling caps.

Table 25. Decoupling Capacitor Recommendation

 

 

Power Plane/Pins

# Decoupling

Capacitor Value

 

 

 

Capacitors

(µF)

 

 

 

 

3.3

V core

6

0.1

 

 

 

 

3.3

V standby

1

0.1

 

 

 

processor I/F (1.3 – 2.5 V)

1

0.1

 

 

 

 

1.8

V core

2

0.1

 

 

 

 

1.8

V standby

1

0.1

 

 

 

 

5

V reference

1

0.1

 

 

 

 

5

V reference standby

1

0.1

 

 

 

 

 

122

Design Guide

Page 122
Image 122
Intel 820E manual ICH2 Decoupling Recommendations, Decoupling Capacitor Recommendation